• International Journal of Highway Engineering
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• v.17 no.6
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• pp.47-54
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• 2015

PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test. METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at $25^{\circ}C$ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.715-724
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• 2003

It is true that SOC facilities, such as dams, need long life cycles since more time has to be invested for the phases of planning, examination, feasibility study, design, contract, construction, and maintenance. This longer life cycle is easily exposed to the risk. And thus, brings additional cost by the delayed project, convenient loss according to the additional run of use, and benefit lose of not to using the facilities. So, the purpose of this study is to try to find a solution to reduce these time consuming problems which could diminish the whole national competition. Hence, this study is to show efficient, systematical project performance and network model by using reciprocal analyses between the construction period and cost based on economical analysis of each phase of life cycles. In addition, on the basis of these outputs, the Fast Track Method is suggested as an alternative solution as a new Approach in Life Cycle's Analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.11
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• pp.940-947
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• 2012

The target system is a middle size UAV, which is a low-speed long-endurance UAV with a weight of 18 kg and wingspan of 6.4 m. Three electric power sources, i.e. solar cells, a fuel cell, and a battery, are considered. The optimal takeoff time is determined to maximize the endurance because the generated solar cell's energy is heavily dependent on it. Each power source is modeled in Matlab/Simulink, and the component models are verified with the component test data. The component models are integrated into a power system which is used for power simulations. When takeoff time is at 6 pm and 2 am, it can supply the power during 37.5 hrs and 27.6 hrs, respectively. In addition, the thermostat control simulation for fuel cell demonstrates that it yields more power supply and efficient power distribution.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.111-124
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• 2002

The ferroelectric RAM (FeRAM) has a great advantage for a system on a chip (SOC) and mobile product memory, since FeRAM not only supports non-volatility but also delivers a fast memory access similar to that of DRAM and SRAM. This work develops at three levels: 1) low voltage operation with boost voltage control of bitline and plateline, 2) reducing bitline capacitance with multiple divided sub cell array, and 3) increasing chip performance with write operation sharing both active and precharge time period. The key techniques are implemented on the proposed hierarchy bitline scheme with proposed hybrid-bitline and high voltage boost control. The test chip and simulation results show the performance of sub-1.5 voltage operation with single step pumping voltage and self-boost control in a cell array block of 1024 ($64{\;}{\times}{\;}16$) rows and 64 columns.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.30-36
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• 2010

In recent memories, repair is an unavoidable method to maintain its yield and quality. Although many word oriented memories as well as embedded memories in system-on-chip (SOC) consists of multiple local memory blocks with a global spare architecture, most of previous studies on built-in redundancy analysis (BIRA) algorithms have focused on single memory block with a local spare architecture. In this paper, a new BIRA algorithm for multiple blocks with a global spare architecture is proposed. The proposed BIRA is basd on CRESTA which is able to achieve optimal repair rate with almost zero analysis time. In the proposed BIRA, all repair solutions for local memory blocks are analyzed by local analyzers which belong to each local memory block and then compared sequentially and judged whether each solution can meet the limitation of the global spare architecture or not. Experimental results show that the proposed BIRA achieves much faster analysis speed compared to previous BIRAs with an optimal repair rate.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2203-2208
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• 2007

Three possible binding modes of cationic meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) to d[(GCATATATGC)2] duplex were investigated by the molecular dynamics (MD) simulation. Among the three binding modes namely, “along the groove”, “across the groove” and “face on the groove”, the “across the groove” model exhibited the largest negative binding free energy and the DNA backbone remained as the B form. In this model, the molecular plain of the TMPyP tilts 45o with respect to the DNA helix axis and is largely exposed to the solvent. TMPyP was stabilized mainly by the interaction between the positively charged neighboring pyridinium moieties of TMPyP and negatively charged phosphate groups of DNA. The result obtained in this work by MD and the report (Jin, B. et al., J. Am. Chem. Soc. 2005, 127, 2417.) that the spectral properties of poly[d(A-T)2] bound TMPyP in the presence and absence of the minor groove binding drug 4',6- diamidino-2-phenylindole are similar, we propose that TMPyP bind across the minor groove of the AT rich- DNA.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.471-479
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• 2010

Forest roads of 16,424km have been constructed as infrastructure for efficient management of forest. The demand of forest road have been also increased steadily with SOC conception for forest management and wood production. But, accuracy verification by completion drawing of forest road needed aspects extration of geographic information to sound like forest road construction and completion drawing. However, verification for completion drawing has not ascertained. This study carried out the evaluation for position accuracy about constructed forest road in Chungcheongnam-do for evaluating horizontal position accuracy of completion drawing of forest road. In result, first of distance of completion drawing and real route designed completion drawing longer than the real route as Gongju 83m, Seosan 66m, Nonsan 27m and Dangjin 19m, respectively. Second, RMSE by point-correspondence was 11m~14.7m, buffering analysis appeared difference of 18~24m. Finally, index of shape was the similar completion and real route through 6.5~7.4 and data information of forest road corresponds to be perfect. For such reasons, the existing completion drawings have a problem that it cannot use graphic information for drawing digital map according to the regulation, and there is an urgent need for improvement to solve this problem in the process of design and construction.

• Progress in Medical Physics
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• v.19 no.1
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• pp.21-34
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• 2008

The parallel Monte Carlo electron and photon transport (PMCEPT) code [Kum and Lee, J. Korean Phys. Soc. 47, 716 (2006)] for calculating electron and photon beam doses has been developed based on the three dimensional geometry defined by computed tomography (CT) images and implemented on the Beowulf PC cluster. Understanding the limitations of Monte Carlo codes is useful in order to avoid systematic errors in simulations and to suggest further improvement of the codes. We evaluated the PMCEPT code by comparing its normalized depth doses for electron and photon beams with those of MCNP5, EGS4, DPM, and GEANT4 codes, and with measurements. The PMCEPT results agreed well with others in homogeneous and heterogeneous media within an error of $1{\sim}3%$ of the dose maximum. The computing time benchmark has also been performed for two cases, showing that the PMCEPT code was approximately twenty times faster than the MCNP5 for 20-MeV electron beams irradiated on the water phantom. For the 18-MV photon beams irradiated on the water phantom, the PMCEPT was three times faster than the GEANT4. Thus, the results suggest that the PMCEPT code is indeed appropriate for both fast and accurate simulations.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.101-104
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• 2008

Recently, the serious damage by earthquakes is increased around the world. SOC fo city is established to minimize the loss of lives and assets by earthquakes, which an objective standard is required. Generally, bridges damage by earthquakes occurred the inelastic hinge under the column. Nonlinear element model of inelastic hinge have been used to Bilinear model, but Takeda model for material characterization of concrete is a little. In this study, railway bridge was performed seismic fragility analysis for Takeda model and Bilinear model comparatively. This analysis shows that damage probability of Takeda model is larger than Bilinear model. And analysis of Takeda model in longitudinal direction and transverse direction are different. Therefore developed analysis for concrete column of bridge is expected to apply to material characterization.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.54-64
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• 2002

Recently System On a Chip(SoC) design based on IP cores has become the trend of If design To prevent the testing problem from becoming the bottleneck of the core-based design, defining of an efficient test architecture and a successful test methodology are mandatory. This paper describes a test architecture and a test control access mechanism for SoC based on IEEE 1149.1 boundary,scan. The proposed SoC test architecture is fully compatible with IEEE P1500 Standard for Embedded Core Test(SECT), and applicable for both TAPed cores and Wrapped cores within a SOC with the same test access mechanism. Controlled by TCK, TMS, TDI, and TDO, the proposed test architecture provides a hierarchical test feature.